How to determine when Fragment becomes visible in ViewPager

Question

Problem: Fragment onResume() in ViewPager is fired before the fragment becomes actually visible.

For example, I have 2 fragments with

Answer 1

setUserVisibleHint(boolean visible) is now deprecated So this is the correct solution

FragmentPagerAdapter(fragmentManager, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT)

In ViewPager2 and ViewPager from version androidx.fragment:fragment:1.1.0 you can just use onPause() and onResume() to determine which fragment is currently visible for the user. onResume() is called when the fragment became visible and onPause when it stops to be visible.

To enable this behavior in the first ViewPager you have to pass FragmentPagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT parameter as the second argument of the FragmentPagerAdapter constructor.